Tetras will work, even barbs, just provide alot of hiding spaces, idk if you plan on adding what are they corys? never seen those, but BNP. Just noticed the RTS that I had really liked hiding places claimed his own side of tank, but never bothered my BNP's. I had rock work from a cichlid tank I used before, so this worked good. Show a pic when you get it set up, would like to see :)